All champions are shared tap - there is no need to be in the same party as whoever initially did damage to the mob. As long as the player is on the champion's threat table, he or she should get some loot.

Courtesy of [wowmartiean]This video shows the rare mentioned above as well as the others in this particular zone, so players can get a better feel for what surrounds said mobs, and what to expect. The video may also show some slightly different tactics.